Equilibrium - 5th Flashcards
1
Q
what are reversible chemical reactions?
A
they can go backwards as well as forwards
2
Q
example of a reversible reaction
A
the decomposition of N2O4
3
Q
what does whether a reversible reaction go forwards or backwards depend on?
A
the amount of reactants and products and the conditions (such as temperature and pressure)
4
Q
what does the decomposition of the above reaction show?
A
- forwards (colourless to brown)
- backwards (brown to colourless)
5
Q
what is the enthalpy change for a reversible reaction?
A
- refers to the forwards reaction
- for the backwards reaction, delta h is the same
6
Q
what is the dehydration of copper sulfate?
A
- a classic reversible reaction
- CuSO4 . 5H2O <-> CuSO4 + 5H2O
7
Q
how to make the reaction of the dehydration of copper sulfate go forwards?
A
- you heat hydrated copper sulfate (CuSO4 . 5H2O)
- the crystals turn from blue to white as they lose all their water
8
Q
how to make the reaction of the dehydration of copper sulfate go backwards?
A
- you add water to anhydrous copper sulfate (CuSO4)
- the white powder absorbs the water and turns blue in the process
9
Q
what is another example of a reversible reaction?
A
- the thermal decomposition of ammonium chloride (NH4Cl)
- NH4Cl (s) <-> NH3 (g) + HCl (g)
10
Q
how do you make the reaction go forwards?
A
- you heat NH4Cl (s)
- nothing appears to change, because NH3 and HCl are both colourless gases
11
Q
how do you make the reaction go backwards?
A
